首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2588049篇
  免费   185082篇
  国内免费   7570篇
耳鼻咽喉   34274篇
儿科学   85249篇
妇产科学   71594篇
基础医学   363675篇
口腔科学   69854篇
临床医学   234560篇
内科学   515559篇
皮肤病学   62478篇
神经病学   213516篇
特种医学   99885篇
外国民族医学   736篇
外科学   386455篇
综合类   50403篇
现状与发展   5篇
一般理论   968篇
预防医学   196234篇
眼科学   56671篇
药学   188008篇
  8篇
中国医学   5333篇
肿瘤学   145236篇
  2021年   19986篇
  2019年   20627篇
  2018年   29293篇
  2017年   22594篇
  2016年   26230篇
  2015年   29512篇
  2014年   40449篇
  2013年   60447篇
  2012年   80253篇
  2011年   84519篇
  2010年   51017篇
  2009年   49173篇
  2008年   79050篇
  2007年   83861篇
  2006年   85586篇
  2005年   81760篇
  2004年   78762篇
  2003年   76067篇
  2002年   73358篇
  2001年   128430篇
  2000年   131348篇
  1999年   110516篇
  1998年   31262篇
  1997年   27928篇
  1996年   28227篇
  1995年   27389篇
  1994年   25076篇
  1993年   23423篇
  1992年   85171篇
  1991年   81578篇
  1990年   78798篇
  1989年   76072篇
  1988年   69480篇
  1987年   68009篇
  1986年   63557篇
  1985年   60520篇
  1984年   44949篇
  1983年   37957篇
  1982年   22463篇
  1981年   19991篇
  1979年   38965篇
  1978年   27449篇
  1977年   23258篇
  1976年   21506篇
  1975年   22816篇
  1974年   26797篇
  1973年   25378篇
  1972年   23759篇
  1971年   21960篇
  1970年   20185篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
972.
Protracted or recurrent pain and inflammation in the early neonatal period may cause long-lasting changes in central neural function. However, more research is necessary to better characterize the long-term behavioral sequelae of such exposure in the neonatal period. Objectives: (1) to study whether timing of postnatal exposure to persistent inflammation alters responsiveness to thermal pain in the adult animal; (2) to assess whether animals experiencing early postnatal chronic inflammation display altered anxiety related behavior; (3) to study the importance of genetic background. Newborn mice (outbred strain, CD1 and F1 hybrid strain, B6C3F1) received an injection of Complete Freund's Adjuvant (CFA) or saline on either postnatal day 1 or 14 (PND1; PND14) into the left hind paw. Pain to radiant heat and anxiety were examined in 12-week-old adult animals. Adult baseline PWL was significantly decreased in CD1 mice exposed to CFA on PND 1 and 14 as compared to their saline treated counterparts. B6C3F1 mice exposed to CFA on PND14 showed markedly reduced baseline PWL compared to the PND14 saline group. Persistent inflammation experienced by B6C3F1 mice on PND1 failed to affect baseline adult thermal responsiveness. Adult mice, CD1 and B6C3F1, displayed low anxiety traits only if they had been exposed to persistent inflammation on PND1 and not on PND14. Our research suggests a role for genetic background in modulating long-term behavioral consequences of neonatal persistent inflammation: the data support the hypothesis that pain experienced very early in life differentially affects adult behavioral and emotional responsiveness in outbred (CD1) and hybrid mice (B6C3F1).  相似文献   
973.
974.
Contrary to popular beliefs, a recent empirical study using eye tracking has shown that a non-clinical sample of socially anxious adults did not avoid the eyes during face scanning. Using eye-tracking measures, we sought to extend these findings by examining the relation between stable shyness and face scanning patterns in a non-clinical sample of 11-year-old children. We found that shyness was associated with longer dwell time to the eye region than the mouth, suggesting that some shy children were not avoiding the eyes. Shyness was also correlated with fewer first fixations to the nose, which is thought to reflect the typical global strategy of face processing. Present results replicate and extend recent work on social anxiety and face scanning in adults to shyness in children. These preliminary findings also provide support for the notion that some shy children may be hypersensitive to detecting social cues and intentions in others conveyed by the eyes. Theoretical and practical implications for understanding the social cognitive correlates and treatment of shyness are discussed.  相似文献   
975.
When studying histological characteristics of human and porcine pancreata in relation to islet isolation, we encountered a remarkably high number of hyperemic islets. The abnormalities observed in these islets ranged from a single dilated vessel through multiple widely dilated vessels to hemorrhages extending into the surrounding exocrine tissue. We determined their possible relevance for outcomes of islet isolation. This study involved a histological examination of 143 porcine pancreata (72 juvenile and 71 adult) and islet isolation from 48 adult pancreata. Human pancreata obtained from 71 multiple organ donors yielded islet isolation in 24 cases. To determine their endocrine content, tissue samples were stained with Aldehyde Fuchsin. The presence of hyperemic islets was scored semiquantitatively with pancreata allotted to categories based on the severity. In humans and pigs we observed hyperemic islets in 48% of pancreata, but only 4.0 ± 2.4% of the islets were hyperemic. In both humans and pigs, significantly higher endocrine content was found in the most severely affected pancreata. When the higher endocrine content was taken into account and isolation results were expressed as ratios of yield and content, we observed significantly lower yields in the most affected pancreata in pigs with a trend toward lower yields in humans. A substantial proportion of human and porcine pancreata contain hyperemic islets. Although the results in humans are preliminary, our data suggest that this phenomenon may contribute to the unpredictable, highly variable islet yields in pigs and humans.  相似文献   
976.
Upper gastrointestinal (GI) bleeding remains a significant cause of mortality and morbidity among renal transplant recipients. We retrospectively analyzed the records of patients who received renal transplantations between January 2001 and July 2007 using mycophenolate mofetil (MMF) in their immunosuppressive regimens. The following data were recorded for those subjects with upper GI bleeding during the first month after transplantation (group B, cases): age, sex, acute rejection episodes, pretransplant upper GI endoscopic findings, Helicobacter positivity, and cytomegalovirus (CMV) seropositivity. The same parameters were studied among a group of patients, who did not have a history of upper GI bleeding (group A, controls). A statistical analysis was performed to ascertain potential risk factors. Among 523 patients (311 females, 212 males) of age range 7 to 58 years, 27 (5.2%) had upper GI bleeding: 13 males and 14 females of mean age 44 ± 12 years. The most frequent endoscopic finding was erosive gastritis (n = 13; 48.1%) followed by duodenal ulcers. Binary logistic regression analysis comparing the 2 groups showed that acute rejection episodes (P = .015) and active CMV infection (P = .046) were the most prominent risk factors for upper GI bleeding during the first month after renal transplantation.  相似文献   
977.
Aims: To explore the quality of life in patients treated medically during the acute phase of pancreatitis as well as at 2 and 12 months after discharge from the hospital. Patients: 40 patients were studied. The etiology of the pancreatitis was biliary causes in 31 patients and non-biliary causes in 9; mild disease was present in 29 patients and severe disease in 11. 30 patients completed the two surveys at 2 and 12 months after hospital discharge. Methods: The SF-12 and EORTC QLQ-C30 questionnaires were used for the purpose of the study. Results: The two physical and mental component summaries of SF-12, all the domains of EORTC QLQ-C30 (except for physical functioning and cognitive functioning) and some symptom scales of EORTC QLQ-C30 (fatigue, nausea/ vomiting, pain, and constipation) were significantly impaired during the acute phase of pancreatitis. There was a significant improvement in the SF-12 physical component summary, and global health, role functioning, social functioning, nausea/vomiting, pain, dyspnea, and financial difficulties (EORTC QLQ-C30) at 2 months after discharge as compared to the basal evaluation. Similar results were found after 12 months except for the mental component score at 12-month evaluation, which was significantly impaired in acute pancreatitis patients in comparison to the norms. The physical functioning of the EORTC QLQ-C30 at basal evaluation was significantly impaired in patients with severe pancreatitis in comparison to patients with mild pancreatitis. Conclusions: Two different patterns can be recognized in the quality of life of patients with acute pancreatitis: physical impairment is immediately present followed by mental impairment which appears progressively in the follow-up period.  相似文献   
978.
979.
980.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号